Mac 1 always had a 'long range'pistol.
I myself shoot with a Tau 7 Silhouet. Barrel is 2" longer than standard.
It can hold all its shots in the 10 ring of a 25m card if I can (at 25m ofcourse).
Downside of upping power with co2's with stronger springs etc usually is, that the self regulating ability diminishes.